mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-30 04:41:49 +00:00
d616ebea23
Summary: Closes https://github.com/facebook/rocksdb/pull/2226 Differential Revision: D4967547 Pulled By: siying fbshipit-source-id: dd3b58ae1e7a106ab6bb6f37ab5c88575b125ab4
130 lines
3.3 KiB
C++
130 lines
3.3 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under the BSD-style license found in the
|
|
// LICENSE file in the root directory of this source tree. An additional grant
|
|
// of patent rights can be found in the PATENTS file in the same directory.
|
|
// This source code is also licensed under the GPLv2 license found in the
|
|
// COPYING file in the root directory of this source tree.
|
|
#pragma once
|
|
|
|
#include <list>
|
|
#include <memory>
|
|
#include <string>
|
|
|
|
#include "include/rocksdb/comparator.h"
|
|
#include "util/arena.h"
|
|
#include "util/mutexlock.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
//
|
|
// CacheWriteBuffer
|
|
//
|
|
// Buffer abstraction that can be manipulated via append
|
|
// (not thread safe)
|
|
class CacheWriteBuffer {
|
|
public:
|
|
explicit CacheWriteBuffer(const size_t size) : size_(size), pos_(0) {
|
|
buf_.reset(new char[size_]);
|
|
assert(!pos_);
|
|
assert(size_);
|
|
}
|
|
|
|
virtual ~CacheWriteBuffer() {}
|
|
|
|
void Append(const char* buf, const size_t size) {
|
|
assert(pos_ + size <= size_);
|
|
memcpy(buf_.get() + pos_, buf, size);
|
|
pos_ += size;
|
|
assert(pos_ <= size_);
|
|
}
|
|
|
|
void FillTrailingZeros() {
|
|
assert(pos_ <= size_);
|
|
memset(buf_.get() + pos_, '0', size_ - pos_);
|
|
pos_ = size_;
|
|
}
|
|
|
|
void Reset() { pos_ = 0; }
|
|
size_t Free() const { return size_ - pos_; }
|
|
size_t Capacity() const { return size_; }
|
|
size_t Used() const { return pos_; }
|
|
char* Data() const { return buf_.get(); }
|
|
|
|
private:
|
|
std::unique_ptr<char[]> buf_;
|
|
const size_t size_;
|
|
size_t pos_;
|
|
};
|
|
|
|
//
|
|
// CacheWriteBufferAllocator
|
|
//
|
|
// Buffer pool abstraction(not thread safe)
|
|
//
|
|
class CacheWriteBufferAllocator {
|
|
public:
|
|
explicit CacheWriteBufferAllocator(const size_t buffer_size,
|
|
const size_t buffer_count)
|
|
: cond_empty_(&lock_), buffer_size_(buffer_size) {
|
|
MutexLock _(&lock_);
|
|
buffer_size_ = buffer_size;
|
|
for (uint32_t i = 0; i < buffer_count; i++) {
|
|
auto* buf = new CacheWriteBuffer(buffer_size_);
|
|
assert(buf);
|
|
if (buf) {
|
|
bufs_.push_back(buf);
|
|
cond_empty_.Signal();
|
|
}
|
|
}
|
|
}
|
|
|
|
virtual ~CacheWriteBufferAllocator() {
|
|
MutexLock _(&lock_);
|
|
assert(bufs_.size() * buffer_size_ == Capacity());
|
|
for (auto* buf : bufs_) {
|
|
delete buf;
|
|
}
|
|
bufs_.clear();
|
|
}
|
|
|
|
CacheWriteBuffer* Allocate() {
|
|
MutexLock _(&lock_);
|
|
if (bufs_.empty()) {
|
|
return nullptr;
|
|
}
|
|
|
|
assert(!bufs_.empty());
|
|
CacheWriteBuffer* const buf = bufs_.front();
|
|
bufs_.pop_front();
|
|
return buf;
|
|
}
|
|
|
|
void Deallocate(CacheWriteBuffer* const buf) {
|
|
assert(buf);
|
|
MutexLock _(&lock_);
|
|
buf->Reset();
|
|
bufs_.push_back(buf);
|
|
cond_empty_.Signal();
|
|
}
|
|
|
|
void WaitUntilUsable() {
|
|
// We are asked to wait till we have buffers available
|
|
MutexLock _(&lock_);
|
|
while (bufs_.empty()) {
|
|
cond_empty_.Wait();
|
|
}
|
|
}
|
|
|
|
size_t Capacity() const { return bufs_.size() * buffer_size_; }
|
|
size_t Free() const { return bufs_.size() * buffer_size_; }
|
|
size_t BufferSize() const { return buffer_size_; }
|
|
|
|
private:
|
|
port::Mutex lock_; // Sync lock
|
|
port::CondVar cond_empty_; // Condition var for empty buffers
|
|
size_t buffer_size_; // Size of each buffer
|
|
std::list<CacheWriteBuffer*> bufs_; // Buffer stash
|
|
};
|
|
|
|
} // namespace rocksdb
|